There's no question that the New York Islanders are going to need to create space on the salary cap in order to re-sign their pending RFAs (Mathew Barzal, Ryan Pulock, and Devon Toews).
The Isles have just over $3 million in cap space and are looking at $12.6 million of cap space in 2020-21. That's not likely to be enough space to sign all three RFA's let alone any other contract the Isles might bring in to fill gaps in the roster.
The salary cap isn't going up this year (and maybe not for a few years), so that won't bail them out either.